Boris Johnson believes the Irish Border solution will be like London's congestion charge

The Irish border remains a key sticking point in Brexit negotiations.

Boris Johnson has taken to the airwaves to downplay the ongoing concerns over the future of the Irish border after Brexit, by comparing it to London's congestion charge.

Johnson, who was the mayor of London between 2008 and 2016, oversaw the city's congestion charge which was introduced by the previous Labour administration in 2003.

With just over a year until the Brexit transition period begins, the foreign secretary took to BBC Radio 4's Today programme. He said: "We think that we can have very efficient facilitation systems to make sure that there's no need for a hard border, excessive checks at the frontier between Northern Ireland and the Republic.

"There's no border between Islington or Camden and Westminster... but when I was mayor of London we anaesthetically and invisibly took hundreds of millions of pounds from the accounts of people travelling between those two boroughs without any need for border checks whatever."

Johnson added that the comparison between the two was "very relevant" because of the need for pre-booking and electronic checks.

The Irish border question

As it stand there is a frictionless border as both nations are part of the customs union and the single market, but this will cease to be the case in March 2019.

The Westminster government's decision to leave both unions means that new agreements need to be reached over the future of the Irish border.

The EU have made it clear that a border of some kind will need to be imposed because of legal checks needed.

If the UK opts for a very hard Brexit, which would result in the country defaulting onto WTO trade rules, the EU would then impose a series of border checks.

To emphasise that the EU is in control of its borders, they may impose strict rules on border checks. However, in an effort to minimise border backlog, the UK government could opt to carry on as normal and not check the goods that come from Ireland.

The DUP, who are in a confidence and supply deal with the Conservative Westminster government, have warned that they could walk away from any agreements if Northern Ireland remains part of the single market or customs union.